A Near Field Communication (NFC) technology is used for short-range contact communications based on Radio Frequency Identification (RFID), and the communications are achieved by magnetic field coupling between electrical appliances. An NFC payment system is increasingly becoming popular as a novel payment manner. A reader-writer communicates with a tag to realize a single payment. Each of the reader-writer and the NFC tag includes an IC chip for processing a signal and an antenna for transmitting or emitting the signal. Instruction information is transmitted by a magnetic field between NFC coil antennae between the reader-writer and the tag. A short-range high-frequency wireless communication technology ensures that data exchange is realized between two devices over a short range, (the data exchange is realized just over a few decimeters). Because such communication range is relatively short, the NFC payment is safer.
As a mobile phone and a short-range payment become popularized, NFC has been implemented in a mobile device for many performances, and NFC can realize communication by touching a communication or only placing two NFC apparatuses in close proximity to each other. It is used for short-range information processing, data exchange or setting the corresponding configuration of the mobile phone. For example, by storing credit card information and the like, a wireless payment system can accomplish a communication via a virtual wallet by using a touch or short-range communication manner. NFC can also serve as a bootstrap program to set other wireless communications such as Bluetooth. However, since a metal back cover is relatively attractive and durable, a growing number of mobile phones tend to use a metal back cover. However, for an NFC antenna, the metal back cover, especially a full-metal back cover, will block a signal from a magnetic field. The prior art is undesirable in communication when being applied to a mobile phone terminal with the full-metal back cover, and is poor in communication distance and stability.
Recently, many research institutions focus on research and development of NFC antenna with a metal back cover, and obtain a lot of achievements. For example, a slot is opened in the metal back cover, and an NFC coil is placed below it, a current distribution opposite to the coil is formed on the metal back cover by coupling the NFC coil and the metal back cover, such that the metal back cover generates radiation, in short, the metal back cover serves as a signal enhancement antenna, thereby achieving a function of enhancing an antenna performance. By means of a manner of opening the slot in the metal back cover, a corresponding surrounding current is produced around the slot in the back cover, but no current exists in a nonmetal area above the slot.